DID 520DMA2 is the chain that's on my bike right now and came stock. It has gold side plates on it which I believe is the only upgrade to the chain. It probably makes a bit of difference that the hit on the 09' Yamaha is quite a bit more tame than any other year/make 450 out there. The YZ250 2 stroke is not the only bike that likes the "torque lever" used a lot. My 09 450 really needs a heavy dose of clutch work. 20 or so hours are cruising desert trails in Reno. The rest are motocross track riding at Mammoth Bar OHV park in N Cal. This is not the biggest, baddest track around and it isn't a sand track but it is a MX track with plenty of W.O.T. time (2nd -4th gear), Air and sharp banked turns I probably have gotten lucky and took no offense to the comments which I log on to read every morning because of the entertainment factor. I don't mind being the martyr this time...but it's nice to have a "Kimosabe", thanks Cowboy!